Issue 5175 - Reject element hiding filter with empty domain names

compiled/filter/ElemHideBase.cpp

Index: compiled/filter/ElemHideBase.cpp
===================================================================
--- a/compiled/filter/ElemHideBase.cpp
+++ b/compiled/filter/ElemHideBase.cpp
@@ -137,25 +137,27 @@
 
       return converted;
     }
 
     return OwnedString(text);
   }
 }
 
-ElemHideBase::ElemHideBase(Type type, const String& text, const ElemHideData& data)
+ElemHideBase::ElemHideBase(Type type, const String& text,
+    const ElemHideData& data, const ParsedDomains& parsedDomains)
     : ActiveFilter(type, ConvertFilter(text, data.mSelectorStart), false),
       mData(data)
 {
   if (mData.HasDomains())
-    ParseDomains(mData.GetDomainsSource(mText), u',');
+    FillDomains(mData.GetDomainsSource(mText), parsedDomains);
 }
 
-Filter::Type ElemHideBase::Parse(DependentString& text, ElemHideData& data)
+Filter::Type ElemHideBase::Parse(DependentString& text, DependentString& error,
+    ElemHideData& data, ParsedDomains& parsedDomains)
 {
   StringScanner scanner(text);
 
   // Domains part
   bool seenSpaces = false;
   while (!scanner.done())
   {
     String::value_type next = scanner.next();
@@ -201,16 +203,24 @@
 
   data.mSelectorStart = scanner.position() + 1;
 
   // We are done validating, now we can normalize whitespace and the domain part
   if (seenSpaces)
     NormalizeWhitespace(text, data.mDomainsEnd, data.mSelectorStart);
   DependentString(text, 0, data.mDomainsEnd).toLower();
 
+  parsedDomains =
+    ParseDomainsInternal(data.GetDomainsSource(text), u',', false);
+  if (parsedDomains.hasEmpty)
+  {
+    error = u"filter_invalid_domain"_str;
+    return Type::INVALID;
+  }
+
   if (exception)
     return Type::ELEMHIDEEXCEPTION;
 
   if (emulation)
     return Type::ELEMHIDEEMULATION;
 
   return Type::ELEMHIDE;
 }